nsf.lock problem

Our problem is too many userthread. I think that this is cause nsf.lock what is the nsf.lock? and why has nsf.lock too many waiter? Informix Dynamic Server Version 7.31.UC2A -- On-Line -- Up 00:57:36 -- 186688 K bytes Locked mutexes: mid addr name holder lkcnt waiter waittime 283 11082970 nsf.lock 19767 0 19774 0 19762 0 19765 0 19778 0 19776 0 19777 0 19773 0 19754 0 19769 0 19772 0 263135 11dfbed8 slcommon_ct 19754 0 263332 11585ba0 slcommon_ct 19769 0 263371 11369bc0 slcommon_ct 19772 0 263384 1136a2e8 slcommon_ct 19773 0 Informix Dynamic Server Version 7.31.UC2A -- On-Line -- Up 00:57:38 -- 186688 K bytes Locked mutexes: mid addr name holder lkcnt waiter waittime 283 11082970 nsf.lock 19782 0 8 -1 19763 1 19774 1 19761 1 19771 1 19762 0 19778 0 263227 116649d0 slcommon_ct 19761 0 263240 116650f8 slcommon_ct 19762 0 263253 11665820 slcommon_ct 19763 0 263358 11369358 slcommon_ct 19771 0 263398 1136ad68 slcommon_ct 19774 0 263450 11570988 slcommon_ct 19778 0